FFinalistSouthampton · 2027
Renal & urology
AKT · Renal & urology/CKD, RRT & cysticlow yield

Polycystic kidney disease

Inherited (usually autosomal dominant, PKD1/PKD2) progressive renal cyst formation → enlarging kidneys, CKD

Overview

An inherited cystic kidney disease — most commonly autosomal dominant (ADPKD, PKD1/PKD2 mutations) — in which progressive cyst formation enlarges the kidneys and causes hypertension, haematuria, pain and progression to renal failure by middle age. The crucial extra-renal association is intracranial (berry) aneurysms → subarachnoid haemorrhage. Tolvaptan slows progression in selected patients.

Recognise

  • Family history (autosomal dominant); hypertension (often early), loin pain, haematuria, recurrent UTIs/cyst infection, renal stones; bilateral flank masses (enlarged kidneys)
  • Extra-renal: liver cysts, intracranial BERRY ANEURYSMS (subarachnoid haemorrhage), mitral valve prolapse, diverticular disease, abdominal wall hernias
  • Progresses to ESRD typically by the 5th–6th decade; ARPKD (recessive) presents in infancy

Red flags

  • Sudden thunderclap headache → subarachnoid haemorrhage from a ruptured berry aneurysm → emergency
  • Family history of SAH/aneurysm → consider screening (MR angiography)

Differentials & how to tell them apart

Simple renal cystsfew, incidental, no family history, normal function
Acquired cystic disease (dialysis)cysts developing on a background of ESRD/dialysis
Tuberous sclerosis / VHLcysts/angiomyolipomas with the syndromic features
Autosomal dominant polycystic kidney disease — innumerable bilateral renal cysts (CT)

Autosomal dominant polycystic kidney disease — innumerable bilateral renal cysts (CT)

Steven Fruitsmaak / CC BY-SA 3.0 — Wikimedia Commons

Investigations

Renal ultrasound (multiple bilateral cysts; age-adjusted diagnostic criteria with family history); genetic testing if needed; BP, U&Es/eGFR; MR angiography to screen for intracranial aneurysms in selected patients (family history of SAH); liver imaging for cysts.

Management

BP control (ACEi/ARB) + tolvaptan in selected rapid progressors; manage complications/CKD

  1. 1Diagnose on ultrasound (bilateral cysts + family history); control BP tightly with an ACE inhibitor/ARB and manage complications (cyst infection/bleed, stones, pain).Gate: Thunderclap headache → CT for subarachnoid haemorrhage (ruptured berry aneurysm); a family history of SAH warrants MR-angiography screening.
  2. 2Tolvaptan for selected rapidly-progressing ADPKD (monitor LFTs); manage CKD complications and progress to dialysis/transplant at ESRD; offer genetic counselling.
Blood-pressure control (ACE inhibitor/ARB) — rigorous BP control slows progression and reduces CV/aneurysm risk
Tolvaptan (vasopressin V2 antagonist) — slows cyst growth/decline in selected rapidly-progressing ADPKD (monitor LFTs; aquaresis/thirst)
Treat complications — cyst infection/haemorrhage, stones, pain; manage CKD complications; treat/refer aneurysms
RRT for ESRD — dialysis or transplant as it progresses

Key points

Bilateral flank masses + hypertension + haematuria + family history = ADPKD → BP control (ACEi/ARB), tolvaptan in rapid progressors. The killer association is intracranial BERRY ANEURYSM → subarachnoid haemorrhage (thunderclap headache). Also liver cysts, MV prolapse, diverticular disease.

Monitor & prognosis

BP, eGFR trajectory, LFTs on tolvaptan, complication surveillance; aneurysm screening in selected patients.

Progressive to ESRD by middle age in most ADPKD; SAH is the catastrophic complication.

Source: NICE; UK Kidney Association; cross-ref neurology (SAH)